Following on from Racechrono post

Just downloaded the iphone app. Looks really good.
Just need a trackday to test it out!
Produces accelerometer G readings and lap times via gps.
Circuit overlays can be created by you or downloaded for free.
Downloads Include uk circuits as well as European and Worlwide. eg Brands Indy, Brands GP, Cadwell, Bedford Areodrome

The video option can then be combined with the overlays to give you laptimes, position etc.

I bought the app with addons like the video, speedo options. Cost £13 in total or you can buy the basic £3,49 one and add the other options as you go.

Sample video here

Website here

You can also watch via live server access, plus lots more cool features

I used this last year at the nurburgring. It was ok but would be alot better if the gps receiver in the iPhone works at a faster speed.

quote:

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Originally posted by prawnabie
I used this last year at the nurburgring. It was ok but would be alot better if the gps receiver in the iPhone works at a faster speed.

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I have got the tom tom mount, but its for the 3G and haven't tried it to see if the 4 fits in it yet.

Question re. the accelerometers...

Do you need to mount the phone horizontally? I've just downloaded trackmaster onto my HTC which I've had a quick play with but as far as I can see it you'd need to mount it dead flat and inline with travel to get usable readings or am I missing something?

Andy

I've got some speedometer app for free on htc which sounds similar.worked ok on Friday and could even see the detour into the gravel trap on the map it plotted!some of the speeds were little ambitious tho,think it must of been the gps looking signal,spiked to 153mph around the hairpin at Oulton park!

Android users might want to check out
http://www.androidzoom.com/android_applications/sports/trackmaster_mzd.html

Trackmaster is a racing lap timer that works great for autocross, hillclimbs, rally, and track days!

•Lap & Split Times
•Lap Graphs
•Street & Satellite View
•G-Meter
•Speech Enabled
•Bluetooth GPS
•Google Earth,MSExcel
•Twitter,Facebook
•Background Mode


not a free app but looks rather good with just about every feature you could wish for .... and then there are add-ons too!


[Edited on 21-11-10 by RazMan]

The biggest trouble with using any of these is the sample rate of the GPS and accelerometers, they simply aren't fast enough to create meaningful data or timing. OK for a nice visual overlay, but as a performance aid its just not accurate enough. You need a minimum of a 5hz (every 0.2s) ideally 10hz gps receiver

Harry's lap time is capable of using certain external GPS sensors to give higher data rates. Further support will be added in V15. I have the Dual XGPS150 which Lap Timer uses the NMEA stream for better results than the iphone GPS. The XGPS will be supported in v15 to 5 Hz.
Harry has posted a video of the next version, v15, which is due in the spring.
Here:
http://www.youtube.com/watch?v=6pGHaxUw3UA

In the UK I don't use the lap timer to video record, but I have the external GPS sensor velcro'd to the dash and the iphone in the glovebox out of sight, so I cannot be accused of timing.

Harry's website is here:
http://gps-laptimer.de/Home.html
he has some useful information on GPS NMEA streams and update rates.
I have no ties to Harry apart from being a satisfied user.
h